This is the first example of illegitimate ABO-P blood group carbohydrate antigens in gastric adenoca with a biochemical confirmation of the serological findings. The Tj(a-) rbc property is the first example of the very rare pp genotype of the P blood group system and its serum contains three antibodies IgG in character, i.e., anti-P1PPk. The initial titer of the patient, 66 years in 1951, was 1:8 and it was suspected that her antibody content was maintained at a low level because of continuous in vivo absorption on to her gastric adenoca. The high 1:512 titer (resulting from a biological test of a mini-transfusion of incompatible blood) prevented metastasis in this patient, who died in 1973, 22 years after subtotal gastrectomy, at the age of 88. The biochemical analysis of the lyophilized tumor (found by sheer accident after 24 years at -20~C) was completed by my collaborator, Dr. Hakomori, early in 1982. Evidence is provided that: (1) the tumor tissue contained the pentasaccharide P1 while the normal mucosa contained a sialylparagloboside, antigen pp; and (2) the patient's tumor cells were rendered inactive by specific absorption to the long-acting IgG anti-P1. The main feature was the description of a new hybrid glycolipid molecule consisting of paragloboside with a fifth sugar, beta Ga1NAc identical with the determinant of globoside so that this product reacted with antigloboside, but globoside itself--a tetrasaccharide--was not present. The SsU antigens are associated with a much longer chain of amino acids identified by Marchesi as glycophorin B, a number of them glycosylated. Both anti-S and anti-s tested in whites show three types--SS, Ss and ss characteristic of products of two genes of equal dominance. But, in American Blacks, there is a variable quantity of a fourth variety, i.e., S-swith a much higher incidence among African Blacks. Apparently, this type serves to protect the Africans against infestation with the major human malarial parasite P. falciparum. Anti-U is an antibody produced by S-sindividuals with a specificity of anti-S+ anti-s which, however, are not separable by absorption. On immunizing two series of rabbits with SS and ss bloods, it was possible to demonstrate in preliminary experiments production of anti-s provided that the absorptions are carried out by S-sbloods. Both anti-S and anti-s have resulted in HDN but, nevertheless, both antibodies react maximally at lower temperatures even though their antibodies must have IgG properties in order to induce HDN. This aspect will be investigated in joint studies with Dr. Lalezari.